Establishment of a novel small bowel adenocarcinoma cell line using patient‑derived xenografts, which produces CEA and CA19‑9.

Small bowel adenocarcinoma (SBA) is a rare tumor with a poor prognosis. Due to its rarity, the research infrastructure for SBA, including cell lines, is inadequate. The present study established a novel SBA cell line, SiCry-15X, using patient-derived xenografts of SBA. The following criteria were defined for establishment: Long-term culturability, tumorigenicity and similarity with the original tumor. The biological characteristics of the cell line, its sensitivity to anticancer drugs and its ability to produce tumor markers carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) were evaluated. SiCry-15X cells adhered and grew as a monolayer, with a population doubling time of 37 h. Polymerase chain reaction results confirmed the human origin of the cell line, and short tandem repeat analysis revealed that the cells were genetically identical to the original tumor. The 50% inhibitory concentrations of 5-fluorouracil, paclitaxel, irinotecan, oxaliplatin and cisplatin for SiCry-15X were 104.05, 0.24, 63.3, 146.55 and 49.29 µM, respectively. CEA and CA19-9 concentrations in the culture media were markedly elevated. In addition, CEA and CA19-9 levels in the serum of cell-derived xenograft model mice were elevated. Moreover, CEA and CA19-9 were produced by SiCry-15X cells and distributed throughout the blood. Furthermore, increases in serum CEA and CA19-9 of cell-derived xenograft model mice were consistent with the clinical course of the disease. The newly established SBA cell line, SiCry-15X, could be an effective tool for conducting further studies on SBA.